conf: add SCConfNodeChildValueIsFalse to check for false value

New function to check is a value is actually set to a false value.

rust/sys/src/sys.rs

@@ -758,6 +758,11 @@ extern "C" {
         node: *const SCConfNode, key: *const ::std::os::raw::c_char,
     ) -> ::std::os::raw::c_int;
 }
+extern "C" {
+    pub fn SCConfNodeChildValueIsFalse(
+        node: *const SCConfNode, key: *const ::std::os::raw::c_char,
+    ) -> ::std::os::raw::c_int;
+}
 extern "C" {
     pub fn SCConfValIsTrue(val: *const ::std::os::raw::c_char) -> ::std::os::raw::c_int;
 }

src/conf.c

@@ -874,6 +874,26 @@ int SCConfNodeChildValueIsTrue(const SCConfNode *node, const char *key)
     return val != NULL ? SCConfValIsTrue(val) : 0;
 }
 
+/**
+ * \brief Test if a configuration node has a false value.
+ *
+ * If the field does not exist, or has anything other than a false
+ * value, this function will return 0.
+ *
+ * \param node The parent configuration node.
+ * \param name The name of the child node to test.
+ *
+ * \retval 1 if the child node has a false value, otherwise 0.
+ */
+int SCConfNodeChildValueIsFalse(const SCConfNode *node, const char *key)
+{
+    const char *val;
+
+    val = SCConfNodeLookupChildValue(node, key);
+
+    return val != NULL ? SCConfValIsFalse(val) : 0;
+}
+
 /**
  *  \brief Create the path for an include entry
  *  \param file The name of the file

src/conf.h

@@ -82,6 +82,7 @@ const char *SCConfNodeLookupChildValue(const SCConfNode *node, const char *key);
 void SCConfNodeRemove(SCConfNode *);
 void SCConfRegisterTests(void);
 int SCConfNodeChildValueIsTrue(const SCConfNode *node, const char *key);
+int SCConfNodeChildValueIsFalse(const SCConfNode *node, const char *key);
 int SCConfValIsTrue(const char *val);
 int SCConfValIsFalse(const char *val);
 void SCConfNodePrune(SCConfNode *node);